OBJECTIVES: Metastasis is the primary cause of death in osteosarcoma, and current clinical treatments remain limited. BRD4, a key epigenetic regulator, has shown therapeutic promise in various cancers through its inhibition. However, the mechanistic role of BRD4 in osteosarcoma remains poorly understood. This study aims to elucidate the molecular mechanisms by which BRD4 regulate osteosarcoma progression and to explore novel therapeutic strategies. METHODS: Immunofluorescence was used to assess BRD4 expression levels in a tissue microarray containing 80 osteosarcoma samples from different patients. The Gene Expression Omnibus (GEO) dataset (GSE42352, containing survival data from 88 osteosarcoma patients) was downloaded to perform Kaplan-Meier survival analysis based on BRD4 gene expression levels. In vivo, an orthotopic intramedullary osteosarcoma model was established using HOS cells in C57 mice, followed by treatment with varying doses of the BRD4 inhibitor (+)-JQ1. Micro-CT, 3D reconstruction of bone tissue, and HE staining were employed to evaluate pathological changes in bone and intestinal lymph nodes. In vitro, cell viability was measured using the methyl thiazolyl tetrazolium (MTT) assay, while colony formation and Transwell assays assessed proliferative and invasive capacities. Chromatin-bound BRD4 was analyzed via co-immunoprecipitation combined with mass spectrometry (Co-IP/MS), and O-GlcNAc glycosylation sites and glycan chains of BRD4 were identified using Co-IP with Nano-LC MS/MS. Real-time PCR and Western blotting were used to analyze the relative mRNA and protein expression levels of target genes, respectively. RESULTS: BRD4 was positively expressed in 61.25% (49/80) of osteosarcoma tissues. Patients with high BRD4 expression exhibited significantly shorter survival times (P<0.05). In the orthotopic mouse model, intervention with (+)-JQ1, a potent and commonly used BETi, significantly inhibited tumor growth in vivo and reduced bone destruction (P<0.05). (+)-JQ1 treatment significantly suppressed the proliferation (P<0.001), invasion (P<0.001), and migration (P<0.05) of HOS cells. In osteosarcoma cells, BRD4 exhibited O-GlcNAc modifications at both N- and C- C-termini, particularly at Thr73, which is essential for protein stability. This modification also contributed to the activation of the EGFR tyrosine kinase inhibitor resistance pathway (KEGG Pathway: hsa01521). (+)-JQ1 treatment displaced BRD4 from enhancers and downregulated the transcription of pathway-related genes, such as EGFR and PDGFC, thereby suppressing the malignant behavior of osteosarcoma cells. CONCLUSIONS BRD4 promotes osteosarcoma progression via O-GlcNAc modification at Thr73 and plays a crucial role in tumor growth and metastasis.
Osteosarcoma/drug therapy* ; Humans ; Transcription Factors/metabolism* ; Animals ; Cell Cycle Proteins ; Mice ; Bone Neoplasms/drug therapy* ; Azepines/pharmacology* ; Cell Line, Tumor ; Cell Proliferation/drug effects* ; Triazoles/pharmacology* ; Mice, Inbred C57BL ; Nuclear Proteins/metabolism* ; Gene Expression Regulation, Neoplastic ; Male ; Bromodomain Containing Proteins

Extraskeletal Ewing's sarcoma（EES） in the head and neck is extremely rare, with non-specific clinical manifestations, high malignancy, easy recurrence and metastasis, and poor prognosis. This paper reports a case of EES of the parapharyngeal skull base presenting with secretory otitis media as the initial symptom.The treatment consisted of surgery, chemotherapy and radiotherapy. No further metastasis or recurrence was observed during the two years and six months follow-up. Now we reviewed the relevant literatures and summarized the experience of diagnosis and treatment in EES.
Humans ; Otitis Media with Effusion/etiology* ; Sarcoma, Ewing/therapy* ; Skull Base ; Skull Base Neoplasms/therapy*

Osteosarcoma (OS), chondrosarcoma (CS), and Ewing sarcoma (ES) represent primary malignant bone tumors and pose significant challenges in oncology research and clinical management. Conventional research methods, such as two-dimensional (2D) cultured tumor cells and animal models, have limitations in recapitulating the complex tumor microenvironment (TME) and often fail to translate into effective clinical treatments. The advancement of three-dimensional (3D) culture technology has revolutionized the field by enabling the development of in vitro constructed bone tumor models that closely mimic the in vivo TME. These models provide powerful tools for investigating tumor biology, assessing therapeutic responses, and advancing personalized medicine. This comprehensive review summarizes the recent advancements in research on 3D tumor models constructed in vitro for OS, CS, and ES. We discuss the various techniques employed in model construction, their applications, and the challenges and future directions in this field. The integration of advanced technologies and the incorporation of additional cell types hold promise for the development of more sophisticated and physiologically relevant models. As research in this field continues to evolve, we anticipate that these models will play an increasingly crucial role in unraveling the complexities of malignant bone tumors and accelerating the development of novel therapeutic strategies.
Bone Neoplasms/pathology* ; Humans ; Osteosarcoma/pathology* ; Tumor Microenvironment ; Sarcoma, Ewing/pathology* ; Chondrosarcoma/pathology* ; Animals ; Cell Culture Techniques/methods* ; Cell Culture Techniques, Three Dimensional/methods* ; Cell Line, Tumor

Osteosarcoma (OS) is the most prevalent primary malignant bone tumor affecting children and adolescents. Despite ongoing research efforts, the 5-year survival rate has remained stagnant for many years, highlighting the critical need for novel drug development to enhance current treatment protocols. Ziyuglycoside II (ZYG II), a triterpenoid saponin extracted from S. officinalis, has recently demonstrated antitumor properties. This study evaluates the antitumor effect of ZYG II on osteosarcoma and elucidates its mechanism of action through the co-regulation of p53 and estrogen-related receptor gamma (ESRRG), which inhibits disease progression. The research employs in vitro experiments using multiple established osteosarcoma cell lines, as well as in vivo studies utilizing a nude mouse model of orthotopic xenograft osteosarcoma. Additionally, ESRRG shRNA was used to construct stable ESRRG-reducing OS cell lines to investigate the molecular mechanism by which ZYG II exerts its anti-osteosarcoma effects through the co-regulation of ESRRG and p53. Results indicate that ZYG II administration led to decreased OS cell viability and reduced tumor volumes. Furthermore, cell cycles were arrested at the G₀/G₁ phase, while the proportion of apoptotic cells increased. Expression of p53, ESRRG, p21, Bax, Cleaved Caspase-9, and Cleaved Caspase-3 proteins increased, while expression of CDK4, Cyclin D1, and Bcl-2 proteins decreased. Multiple ZYG II and ESRRG docking patterns were simulated through molecular docking. Comparing the pharmacodynamic response of ZYG II to OS cell lines with reduced ESRRG and normal expression demonstrated that ZYG II inhibits osteosarcoma progression, induces cell cycle arrest, and promotes cell apoptosis through the coordination of p53 and ESRRG. In conclusion, ZYG II inhibits osteosarcoma progression, leads to cell cycle arrest, and promotes cell apoptosis through synergistic regulation of p53 and ESRRG.
Osteosarcoma/physiopathology* ; Tumor Suppressor Protein p53/genetics* ; Humans ; Animals ; Saponins/chemistry* ; Bone Neoplasms/physiopathology* ; Signal Transduction/drug effects* ; Cell Line, Tumor ; Mice, Nude ; Mice ; Apoptosis/drug effects* ; Receptors, Estrogen/genetics* ; Mice, Inbred BALB C ; Female ; Male ; Xenograft Model Antitumor Assays

OBJECTIVES: This study aimed to evaluate the diagnostic accuracy of Cyclin D1 as an adjunct immunomarker in CD99 positive small round cell neoplasms with primary consideration of PNET/EWS. MATERIALS AND METHODS: Tissue from 2017 to 2023 with a histopathologic diagnosis of CD99 positive small round blue cell tumors with primary consideration of Primitive Neuroectodermal Tumor (PNET)/Ewing Sarcoma were retrieved and Cyclin D1 immunohistochemical staining done. Diagnostic accuracy of Cyclin D1 immunostaining was determined by calculating the sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: Cyclin D1 immunohistochemical staining was performed in 19 specimens available, of which 13 yielded a positive result. Of these, 8 had a final histopathologic diagnosis of CD99 positive small round blue cell tumor with primary consideration of PNET/Ewing Sarcoma, resulting in sensitivity of 61.54%, specificity of 100%, positive predictive value of 100% and negative predictive value of 50.0%. The overall accuracy is 72.2%. CONCLUSION Cyclin D1 can be used as an adjunct immunomarker to aid in the diagnosis of CD99 positive round cell tumor with primary consideration of PNET/Ewing Sarcoma specifically in resource limited settings where molecular testing is not readily available. Given the high specificity of Cyclin D1 in such cases, it can be used to rule out other small round blue cell tumors that can also stain positive for CD99 such as Rhabdomyosarcoma. However, interpretation must be done in conjunction with the results of other immunohistochemical stains in order to increase its diagnostic accuracy.
Human ; Male,Female ; Cells ; Sarcoma, Ewing ; Sarcoma ; Neuroectodermal tumors, Primitive ; Cyclin D1

Ewing’s sarcoma is a rare cancerous tumor of bone or soft tissue that usually occurs mostly in young adults. The diagnosis of Ewing’s sarcoma in pregnancy, most especially the subtype extraskeletal Ewing’s Sarcoma, is very rare with only few cases published in the literature worldwide. We present a case of a primigravida diagnosed with extraskeletal Ewing’s sarcoma at 6 weeks age of gestation. Currently, because of the rarity of this condition, there is lack of a universal consensus on the recommended therapeutic approach. A multidisciplinary management involving the generalist obstetrician, perinatologist, medical oncologist, and neonatologist was initiated at the outset to provide timely balance between optimal maternal treatment and fetal well-being. The maternal and fetal condition was stable all throughout the course of the chemotherapy using doxorubicin during pregnancy. Close interdisciplinary coordination regarding the treatment plans across these subspecialists resulted in a successful pregnancy outcome.

This study aims to investigate the optimal ratio of Astragali Radix-Curcumae Rhizoma(AC) for inhibiting the proliferation of 143B osteosarcoma cells, and to investigate the mechanism by which AC inhibits osteosarcoma growth and metastasis through angiogenesis and cell adhesion mediated by the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/hypoxia inducible factor-1α(HIF-1α) pathway. A subcutaneous 143B tumor-bearing nude mouse model was successfully established and randomly divided into the model group, and the AC 1∶1, 2∶1, and 4∶1 groups. Body weight, tumor volume, and tumor weight were recorded. Real-time quantitative polymerase chain reaction(RT-qPCR) and Western blot were used to detect the mRNA and protein expression levels of PI3K, Akt, phosphorylated Akt(p-Akt), HIF-1α, vascular endothelial growth factor A(VEGFA), transforming growth factor-β1(TGF-β1), epithelial cadherin(E-cadherin), neural cadherin(N-cadherin), vimentin, matrix metalloproteinase 2(MMP2), matrix metalloproteinase 9(MMP9), B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and caspase-3 in the hypoxic core region of the tumor tissue. A cell hypoxia model was established, and the effects of AC-medicated serum(model group, AC 1∶1, 2∶1, and 4∶1 groups) on angiogenesis, proliferation, adhesion, invasion, and migration of 143B osteosarcoma cells were examined through CCK-8, flow cytometry, Transwell assay, cell adhesion assay, and HUVEC tube formation assay. The results showed that compared with the model group, the tumor weight and volume were smallest in the 2∶1 group. The expression levels of PI3K, Akt, p-Akt, HIF-1α, VEGFA, and TGF-β1 were significantly decreased, and the protein expression of E-cadherin was significantly increased, while the protein expression of N-cadherin, vimentin, MMP2, and MMP9 was significantly decreased. Additionally, the protein expression of Bax and caspase-3 was significantly increased, and Bcl-2 protein expression was significantly decreased. In vitro experiments showed that after intervention with AC-medicated serum at a 2∶1 ratio, the cell activity, adhesion, invasion, and migration of 143B cells were significantly reduced, apoptosis was significantly increased, and HUVEC tube formation was significantly decreased. In conclusion, the 2∶1 ratio of AC showed the most effective inhibition of 143B cell growth. AC can inhibit the growth and metastasis of osteosarcoma 143B cells by regulating the PI3K/Akt/HIF-1α signaling pathway, inhibiting angiogenesis and reducing cell adhesion, invasion, and migration.
Osteosarcoma/pathology* ; Animals ; Proto-Oncogene Proteins c-akt/genetics* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Humans ; Mice ; Cell Adhesion/drug effects* ; Cell Proliferation/drug effects* ; Neovascularization, Pathologic/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Phosphatidylinositol 3-Kinases/genetics* ; Cell Line, Tumor ; Mice, Nude ; Signal Transduction/drug effects* ; Astragalus Plant/chemistry* ; Bone Neoplasms/physiopathology* ; Male ; Rhizome/chemistry* ; Mice, Inbred BALB C ; Angiogenesis

Primary malignant bone tumors are extremely rare. Osteosarcoma, chondrosarcoma, Ewing's sarcoma, and myeloma are the most common malignancy in bone. Osteosarcoma and Ewing's sarcoma are common in children and adolescents, and the tumors are high lethality due to the high rate of pulmonary metastasis. While chondrosarcoma, myeloma, and chordoma are more common in middle aged and elderly people. Japanese Orthopaedic Association (JOA) published the secondary clinical practice guideline on the management of primary malignant bone tumors. We put an emphasis on explanation some important issue of this guideline for help Chinese musculoskeletal tumor professionals in clinical practice.
Humans ; Bone Neoplasms/surgery* ; Chondrosarcoma/therapy* ; Japan ; Orthopedics ; Osteosarcoma/pathology* ; Practice Guidelines as Topic ; Sarcoma, Ewing/therapy* ; Societies, Medical

OBJECTIVE: To explore the effectiveness of artificial hemi-knee prosthesis reconstruction for bone defects after resection of pediatric osteosarcoma. METHODS: A retrospective analysis was conducted on the clinical data of 18 children with osteosarcoma who met the selection criteria and were treated between January 2016 and December 2019. There were 11 males and 7 females, aged 6-10 years (mean, 8.9 years). Osteosarcoma located in the distal femur in 11 cases and the proximal tibia in 7 cases. Among them, 12 cases were conventional osteosarcoma and 6 cases were small cell osteosarcoma, with a disease duration of 1-9 months (mean, 3.1 months). All patients received 2 cycles of preoperative chemotherapy with doxorubicin, cisplatin, and ifosfamide. After en bloc tumor segment resection, bone defects were reconstructed using custom-made artificial hemi-knee prostheses. Rehabilitation training was initiated at 8 weeks postoperatively under the protection of a knee immobilizer brace, combined with 4 cycles of adjuvant chemotherapy. During follow-up, lower limb growth length and limb shortening (compared with the healthy side) were measured, and limb function was evaluated using the Musculoskeletal Tumor Society-93 (MSTS-93) scoring system. RESULTS: All surgeries were successfully completed, with an operation time of 2.0-3.1 hours (mean, 2.4 hours) and intraoperative blood loss of 180-320 mL (mean, 230.0 mL). Incisional edge necrosis occurred in 1 case at 10 days postoperatively, while the incisions of the remaining 17 patients healed by first intention. One case developed periprosthetic infection caused by Staphylococcus aureus at 1 week postoperatively, which was cured after symptomatic treatment. All 18 patients were followed up 60-96 months (mean, 74.2 months). No local tumor recurrence was observed during follow-up. Imaging examinations showed prosthesis loosening in 2 cases, while the prosthesis of other patients were well-positioned. At last follow-up, the knee joint range of motion was 80°-120° (mean, 106.7°). The MSTS-93 score was 16-29 (mean, 24.7), with 12 cases rated as excellent, 5 good, and 1 fair. The patients' height increased by 12.8-20.0 cm (mean, 15.5 cm), the lower limb growth length was 6.0-13.0 cm (mean, 9.7 cm), and limb shortening was 1.8-4.6 cm (mean, 3.1 cm). There was no significant difference in MSTS-93 scores, lower limb growth length, or limb shortening between the distal femur group and the proximal tibia group ( P>0.05). CONCLUSION Artificial hemi-knee prosthesis reconstruction can preserve the adjacent normal epiphysis of the knee joint, maximize limb growth potential, and reduce adult limb length discrepancy, making it a suitable reconstruction option for children with knee osteosarcoma.
Humans ; Osteosarcoma/surgery* ; Male ; Child ; Female ; Knee Prosthesis ; Retrospective Studies ; Bone Neoplasms/surgery* ; Plastic Surgery Procedures/methods* ; Tibia/surgery* ; Femur/surgery* ; Arthroplasty, Replacement, Knee/methods* ; Treatment Outcome ; Chemotherapy, Adjuvant ; Femoral Neoplasms/surgery*

Objective To investigate the effect of basic helix-loop-helix family member E40 (BHLHE40) on the invasion and migration of osteosarcoma (OS) cells, and to explore the role of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway in the biological behavior of OS mediated by BHLHE40, providing a scientific basis for targeted therapy of OS. Methods On the basis of clinical OS samples and OS cell lines, the expression differences of BHLHE40 between OS and adjacent tissues, as well as those between OS cells and normal osteoblast cell lines, were analyzed. BHLHE40 knockdown OS cells were obtained through shRNA transfection. The effects of BHLHE40 on OS cell proliferation, migration, and invasion were examined using CCK-8, EdU staining, wound healing, and Transwell assays. The involvement of the PI3K/AKT signaling pathway was assessed by Western blotting. Further validation was conducted in vivo experiments. Results The expression of BHLHE40 was significantly higher in OS tissues compared to adjacent tissues. In OS cell lines, BHLHE40 protein expression levels were increased compared to normal osteoblasts, and the cell line with the highest BHLHE40 expression was selected for subsequent knockdown experiments. Compared with the knockdown control group, the BHLHE40 knockdown group exhibited reduced cell viability, EdU-positive cell count, colony number, cell migration, and invasion abilities, along with downregulation of phosphorylated PI3K(p-PI3K)/PI3K and p-AKT/AKT protein expression. The aforementioned functions of BHLHE40 were also reproduced in in vivo experiments. Conclusion BHLHE40 is highly expressed in OS tissues, and its knockdown can significantly inhibit OS cell proliferation, migration, and invasion, while reducing PI3K/AKT signaling pathway activity. This suggests that BHLHE40 could serve as a novel therapeutic target for OS.
Osteosarcoma/metabolism* ; Humans ; Proto-Oncogene Proteins c-akt/genetics* ; Cell Proliferation/genetics* ; Cell Movement/genetics* ; Signal Transduction/genetics* ; Phosphatidylinositol 3-Kinases/genetics* ; Cell Line, Tumor ; Animals ; Neoplasm Invasiveness ; Basic Helix-Loop-Helix Transcription Factors/metabolism* ; Bone Neoplasms/metabolism* ; Mice ; Gene Knockdown Techniques ; Male ; Female ; Mice, Nude